Longitude between Cambridge and Salt Lake City.-Not corrected for personal equation.

error. '028

25

7.718 1024

1

6.865

'024

1

14.583 ±'034

7.292

±017

0.853

7.228 £'021

14.560 1036

Mean

3 257-260

1 '007

0.817

ngitude Determinations across the Continent, January and February, 1869. (Final results.)

To correct the differences of longitude for personal equation,

e have:

ART. LVII.- Notice of the Invertebrata dredged in Lake Su
in 1871, by the U. S. Lake Survey, under the direction of
C. B. Comstock, S. I. Smith, naturalist; by S. L. SMITH -
A. E. VERRILL.

(Published by permission.)

DURING the explorations in Lake Superior, mentioned in last number of this Journal (page 373) the following spe were obtained, together with a number of minute forms, w have not been determined.

A full account of the expedition, with descriptions of species collected, will be published in the official report of expedition.

RADIATA.

Hydra carnea Agassiz. A beautiful Hydra, agreeing Ayer's description of this species, was very abundant at eastern end of St. Ignace, upon rocks along the shore and the surface, frequently completely covering quite large surfa where they were protected from the direct sunlight, and also brought up in many of the dredgings from 8 to 148 fathe In 32 fathoms, Neepigon Bay, and in 59 fathoms, off Simme Harbor, it was brought up in abundance from a soft clayey tom. In the deep dredgings, it frequently came up near bottom of the clay in the dredge, and was evidently not can while the dredge was near the surface.

MOLLUSCA.

Limnoa. A species allied to L. disidiosa Say, was abunda among Cladophora in 8 to 13 fathoms on the south side of S Ignace Island.

Physa heterostropha Say. In the cove at the eastern end St. Ignace, in 4 to 6 fathoms, and young specimens, in 8 to 1 fathoms, at the locality with the Limnæa just mentioned. Physa vinosa Gould. A very young specimen, apparently this species, in 6 to 8 fathoms among the Slate Islands.

Planorbis parvus Say. Common in 8 to 13 fathoms on the 1th side of St. Ignace.

Valvatu sincera (Say sp.). Abundant with the last species, 8 to 13 fathoms, and also, in 4 to 6 fathoms, in the cove at e eastern end of the same island.

Sphærium sp. nov.? Among the Slate Islands, in 6 to 8 homs. A single young specimen of another species of Spham was found, in 8 to 13 fathoms, on the south side of St.

ace.

Pisidium Virginicum Bourguignat. On the south side of St. ace, 8 to 13 fathoms.

Pisidium abditum Haldeman. With the last species, in 8 to fathoms, and also, in 4 to 6 fathoms, in the cove at the tern end of the same island.

Pisidium compressum Prime. In the cove at the eastern end St. Ignace, 4 to 6 fathoms.

Pisidium sp. nov. A small, semi-translucent species, the same found by Dr. Stimpson in Lake Michigan, was brought up nearly every dredging. It was common in the cove at the tern end of St. Ignace, on sandy and muddy bottom, in 4 to thoms, and abundant among Cladophora, in 8 to 13 fathoms, the south side of that island; among the Slate Islands, in 6 8 and 12 to 14 fathoms; at 13 to 15 fathoms on a sandy tom in Simmon's Harbor; near Copper Harbor, in 17 fathoms, r sand; in 32 fathoms, very soft clayey mud, in Neepigon ; off Copper Harbor, in 62 fathoms, and north of Keweenaw nt, in 82 fathoms, soft reddish clayey mud and sand; and 11 the deep dredging down to 159 fathoms.

WORMS.

umbricus lacustris Verrill, sp. nov. About 15 inches long, in diameter. Body round, distinctly annulated. Head t, conical, obtusely pointed. Setæ spine-like, strongly ed, acute, arranged two by two, those of each pair close ther. Color reddish brown.

outh side of St. Ignace, among Cadophora, 8 to 13 fathoms. enuris abyssicola Verrill, sp. nov. Worm slender, attenuated eriorly, about 30 of an inch long, 03 in diameter anteriorly. y composed of about 28 segments, those of the posterior elongated; those of the anterior half shorter, separated by it constrictions. Cephalic lobe short, subconical, rounded ont. Mouth large, semi-circular. Intestine slender, moniliA, containing sand. Anus terminal, with three or four slight

S.

Setæ in four, fan-shaped fascicles on each segment, comcing at second segment behind the mouth. The two ral fascicles are separated by a space equal to about twice length of the setæ, of which there are five or six in each cle; the sata are simple, acute, slightly curved, equal to

about one-sixth the diameter of the body. The lateral f contain three to five somewhat shorter and straighter a setæ. One specimen appeared to have four minute ocell. the upper side of the head.

Off Copper Harbor, 17 fathoms, sand; off Simmon's H 60 fathoms; and on the line from the Slate Islands t Stannard Rock, fourth haul, 159 fathoms. Senuris limicola Verrill, sp. nov. Worm more slender the preceding, attenuated posteriorly, composed of abo segments. Length about 33 of an inch, diameter 02. Ce lobe blunt, conical. Setæ in four fascicles upon each seg six to eight in each fascicle anteriorly, four or five poster. The setæ in all the fascicles are relatively long, slender, c and acute. Two tortuous red blood vessels pass along th testine, forming a loop at each segment. Intestine monilt On the line between the Slate Islands and Stannard R fourth haul, 159 fathoms.

Chirodrillus, gen. nov. Allied to Sanuris, but with six shaped fascicles of setæ upon each segment, two of wh are ventral, two lateral, and two sub-dorsal; setæ in the vent and lateral fascicles four to nine, simple, acute, slender, curr like an italic f; those of the dorsal fascicles, stouter and curved, three to six in each fascicle. Intestine wide, some moniliform. Anus terminal, large.

Chirodrillus larviformis Verrill, sp. nov. Body rather sh and not very slender, cylindrical, obtuse at both ends, disting annulated, composed of about 38 rings. Length about 3 an inch; diameter 05. Cephalic lobe short, conical, obt mouth large, semi-circular beneath. Ventral fascicles of near together, with about five setæ, which are rather sh simple, acute, little curved; lateral fascicles with five or s setæ of similar form and size; sub-dorsal ones similar. W preserved in alcohol, the body is usually curved ventrally or a simple coil. Color, when living, translucent whitish, intest slightly greenish. A thickened smooth zone commences behi the 10th setigerous ring, occupying the space of about t segments.

Off Copper Harbor, 17 fathoms, sand; off Simmon's Harb 59 fathoms, clayey mud.

Chirodrillus abyssorum Verrill, sp. nov. Sub-cylindrics thicker anteriorly, distinctly annulated, composed of about segments. Length 25 of an inch; diameter about 02. Cephal lobe short, conical, obtuse, mouth large, semi-circular. Ventra fascicles with eight or nine setæ anteriorly, five or six posterior The setæ are long, slender, acute, strongly curved, those on th inferior side of the fascicles nearly twice as long as those of the upper side; setæ of the lateral fascicles five or six, slender nearly as long as those of the ventral ones, and similar in form,