times does not, the 8th taking its place (pre-axial class of innervation) as well as supplying other fibres also. In the cat, in my own experiments, the post-axial class, as measured by the above standard, has contained a rather larger number of individuals (twenty-two out of thirty-nine).* In experiments on Macacus, also, it early became clear that the types of innervation of the limb-muscles by the spinal roots are conveniently dealt with as two classes. In fifty-two individuals the reactions obtained place the majority (thirty-one) within a pre-axial class, the broad features of which are as follows: : Pre-axial Class of Innervation. No. of the root excited. 1st Subthoracic .. Movement produced. Retraction of abdominal wall, near umbilicus in front. Retraction of lower part of abdominal wall, flexion of hip, with some eversion, drawing up of testicle (stronger than with 3rd). Retraction of lowest part of abdominal wall, drawing up of the testicle, flexion at hip, with marked rotation of thigh outwards and some adduction, some extension of knee. Flexion at hip, extension at knee, adduction of thigh, eversion of thigh. Flexion at hip, extension at knee, adduction of thigh, strong flexion at ankle, drawing up of outer edge of foot, flexion of hallux and digits. Extension at hip, adduction of thigh, flexion at knee, extension at ankle, rotation of leg inwards, lifting of outer edge of foot, flexion of digits and hallux at terminal joint with (sometimes) adduction. Extension at hip, with slight rotation out ward of the thigh, flexion at knee, extension at ankle, flexion of digits and hallux with adduction of hallux, depression and adduction of root of tail, closure of anus. Extension at hip, with slight rotation outward of the thigh, flexion at knee, extension at ankle, strong flexion and adduction of hallux, flexion of digits in "interosseal" position, closure and protrusion of anus, root of tail adducted and depressed, perineum pushed down. This agrees with the observations by Langley, loc. cit. Movement produced. Adduction of root of tail, which is drawn toward the side stimulated. Proximal half of tail drawn toward side stimulated. Muscle thrown into action. Quadratus lumborum, psoas parvus, external oblique, internal oblique, transversalis. Quadratus lumborum, psoas magnus, cremaster, external oblique, internal oblique, transversalis. Psoas, cremaster, iliacus, external oblique, internal oblique (lower part only), transversalis, pectineus, adductor longus, sartorius (upper part especially), vastus internus, and obdurator externus slightly. Psoas, iliacus, pectineus, adductor longus, sartorius (lower part especially), vastus internus (> vastus externus), crureus, obturator, rectus femoris, vastus externus, gracilis. Gracilis, vastus externus (> vastus internus), Tibialis anticus, extensor longus digitorum, extensor proprius hallucis, peroneus longus, No. of root excited. Muscle thrown into action. slight (<peroneus brevis), peroneus brevis, gastrocnemius external head, internal head, plantaris, tibialis posticus, flexor longus digitorum, soleus, flexor longus hallucis, extensor brevis digitorum, flexor brevis digitorum, adductor hallucis, adductor minimi digiti, flexor accessorius, flexor brevis hallucis, flexor brevis minimi digiti, interossei and lumbricales, obturator internus, quadratus femoris, gemelli superior et inferior, pyriformis (the larger part of, especially the lateral part), deeper part of sphincter ani, semitendinosus, semimembranosus, biceps, adductor magnus (part of), popliteus, gluteus medius. 8th Subthoracic.. Biceps (< than semimembranosus), semitendi 9th nosus (< than semimembranosus), semimembranosus, gluteus maximus, gluteus medius, gastrocnemius internal head (< than external), external head, soleus, adductor hallucis, flexor accessorius, adductor minimi digiti, adductor hallucis, obturator internus, quadratus femoris (slight), gemelli superior et inferior, pyriformis (small part, chiefly mesial), sphincter ani, flexor brevis hallucis, flexor brevis minimi digiti, lumbricales and interossei. Sphincter vaginæ, obturator internus (slightly). The remaining twenty-one individuals formed a "post-axial" class, with the following broad characters in common: Movement. Retraction of abdominal wall. Retraction of lower part of abdominal wall, Movement. hip, with adduction of thigh, extension at knee, slight rotation outwards of thigh. Flexion at hip, with adduction of thigh, extension at knee, drawing up of inner edge of foot, with slight flexion at ankle, and slight extension of hallux. Extension at hip, with adduction of thigh, flexion at knee, flexion at ankle, lifting of outer edge of foot, extension of toes, with adduction of hallux. Extension at hip, flexion at knee, extension at ankle, tilting of outer edge of foot, flexion. of digits, with strong adduction of hallux, depression of root of tail, slight rotation outward of the thigh. Slight rotation outward of the thigh, extension at hip, flexion at knee, extension (very strong) at ankle, strong flexion and adduction of hallux, flexion of digits in "interosseal" position, contraction of anus, root of tail depressed and drawn to side stimulated. Slight rotation outwards of the thigh, flexion of digits, perineum pushed down, contraction of anus, abduction of root of tail toward side stimulated. Abduction of root of tail toward side stimulated. Proximal two-thirds of tail drawn toward side stimulated. Distal half of tail drawn toward side stimulated. Tip of tail drawn toward side stimulated. Post-axial Class. 1st Subthoracic.. Quadratus lumborum, psoas parvus, external oblique, internal oblique, transversalis. Quadratus lumborum, psoas magnus, cremaster, external oblique, internal oblique, transversalis. Psoas magnus, cremaster, iliacus, external oblique, transversalis (the lower part only of the three latter), pectineus, adductor longus, sartorius. Psoas magnus, iliacus, pectineus, the adductor longus, gracilis (probably the rest of the adductor mass), sartorius, vastus internus, vastus externus, crureus, rectus fem. (slight), obturator externus. Gracilis, adductor longus (slight), tensor vaginæ femoris, rectus femoris, vastus internus, vastus externus, crureus, tibialis anticus, peroneus longus, semimembranosus (these latter only slightly), extensor hallucis (very slight). Part of adductor magnus, tibialis anticus, ex tensor longus digitorum, extensor hallucis, peroneus longus, peroneus brevis, short (intrinsic) extensors of the digits, abductor minimi digiti, gastrocnemius (both heads, but slight), popliteus, tibialis posticus, flexor longus digitorum, long flexor of the hallux, soleus, semimembranosus, plantaris, semitendinosus, biceps. Adductor magnus, semitendinosus, semimem- semimembranosus, semitendinosus, gluteus medius, gastrocnemius (both heads), soleus, tibialis posticus, flexor longus digitorum, abductor hallucis, abductor natum, short and accessory flexor of the digits and hallux, adductor of the hallux, interossei and lumbricales, sphincter ani, sphincter vaginæ, small part of pyriformis, obtu |