40 MARINE INVERTEBRATA OF GRAND MANAN. 



low-water mark. It rarely occurs here, although so common on the southwestern 

 portions of the coast of Maine. 



Idot.ea montosa, St., n. s. Body elongated ovate, abruptly narrowing at the 

 commencement of the abdomen. The back seems divided longitudinally into three 

 unequal lobes, of which the middle one is by far the largest. This results from the 

 prominent, Avell-defmed, rounded lolx^s into which the segments expand at each 

 extremity of their width. The lateral incisions, separating these segments, reach, 

 in depth, the margin of the middle lobe of the back. The abdomen in length 

 equals six-tenths that of the thorax, and has its segments soldered together, except 

 that slight transverse depressed lines indicate two short^ anterior segments, Avhich 

 bear a large rounded knob in their middle ; and one scutiform posterior segment, 

 which also bulges up strongly in the middle; this latter protuberance being separated 

 from the former by a deep depression. The antennas are very small; the internal or 

 superior ones much the longest, reaching the second thoracic segment ; the external 

 ones about half the length of the internals, and without an articulated flagellum. 

 The feet are identical in character throughout, each terminating in a delicate, 

 elongated, subcheliform hand, with a very slendei-, almost acicular finger or nail. 

 The first pair is shortest ; they then increase in length to the fifth, which is longest, 

 and then decrease vei'y slightly to the seventh and last pair. The opercular abdo- 

 minal appendages are margined with a sharp elevated ridge, and have very minute 

 articulated pieces at their posterior extremities, and elongated subsidiary pieces for 

 about half their length anteriorly and interiorly. The color is dark grayish- 

 Length, 0.4 in. ; greatest breadth, at the fourth segment, 0.19 in. ; length of a foot of 

 the fifth pair, 0.2 in. Taken in deep water on sandy and muddy bottoms. The 

 characters of the antenujB would, strictl}^, exclude this species from Idotcca. It 

 belongs to a group of which I have three or four species from the New England 

 coast, and which will probably be found to constitute a new genus. 



J^RA COPIOSA, St., n. s., Fig. 29. Body suboblong, narrowing slightly at each ex- 

 tremity, and a little convex above. Head rather large, with the small but very obvi- 

 ous black eyes near its posterior corners; thoracic segments not widely separated at 

 their hairy external edges, but far apart along the middle ; abdomen with three 

 segments, of which the anterior two are very small and nai'row, and the posterior 

 one broad, with its caudal appendages very minute and close together in a niche at 

 its posterior extremity. The thick-based internal antenna) are about one-third the 

 length of the i*ather stout external ones, which reach the third segment of the body. 

 Feet weak and slender, all of the same character, terminating in a sharp nail. 

 Branchial lamina or operculum, considerably smaller than the abdominal cavity. 

 Color above grayish, punctate ; those with eggs are bright green below. Length, 

 0.2 in.; greatest breadth, at the third segment, 0.1 in. Found in great numbers on 

 our whole New England coast north of Cape Cod, living on the under surfaces of 

 stones in the first (upper) subregion of the littoral zone. At Grand Manan, it was 

 most frequent in sheltered situations. 



' By tlie length of a segment, is meant its extent longitudinal with the body, so that its width in Isopods 

 is almost always much greater than its length. 



