88 REPORT OF COMMISSIONER OF FISH AND FISHERIES. O^l 



alive on the bottoms of vessels, and especially such as have recently 

 arrived from the West Indies and other foreign countries. Tln-sc 

 resemble, in general appearance. L. fascicularis, (Plate VII, fig. 33,) 

 which is a common indigenous species, usually found adhering to floating 

 sea-weeds and other small objects in earl}' summer, in large numbers. 

 It is doubtful whether any of those found on the bottoms of vessels 

 can be regarded as true natives of this region. The most common of 

 them is L. anatifera; the valves of its shell are bordered with orange. 

 The other common species are L. anserifera and L. pectinata. Species 

 of the curious genus, Conchoderma, also occur on the bottoms of vessels. 



Among the Crustacea that commonly occur among the ascidians, 

 hydroids, and algae on the piles of wharves, are Panopeus Sayi, (p. 312,) 

 P. depressus, (p. 312, Plate I, fig. 3,) Gammarus ornatus, (p. 314, Plate IV T 

 fig. 15,) Amphithoe compta S., (p. 370,) Corophium cyUndricum^ (p. 370,) 

 Melita mUda, (p. 314,) Caprclla, sp., (p. 31(3,) and various small Eutoinos- 

 traca. Jcera copiosa (p. 315) often occurs abundantly near high- wa tin- 

 mark, on old piles and timber, living in the crevices and cracks, or 

 under loosened bark. 



Of Annelids very few if any species occur that are peculiar to these sit- 

 uations. The Potamilla oculifera (p. 322, Plate XVII, fig. 80) is quite 

 common on the piles of wharves where the water is pure. P. micropli- 

 thahnaV. (p. 323) also occurs under the same circumstances, and also on 

 the piles in harbors, where the water is brackish. 



The Leprcca rubra V. was found living in tubes among the ascidians 

 on the piles of the wharves. This is a Terebelloid worm, somewhat 

 resembling the Amphitrite ornata, (Plate XVI, fig. 82,) bwt is much 

 smaller, and there are fascicles of setrc on all the segments. There are 

 three pairs of arborescently divided branchia*, which are pedunculated, 

 the last pair being quite small. The body is bright red, the tentacles 

 pale flesh-color. 



The Nicolea simplex V. (p. 321,) was also found with the last in large 

 numbers, but mostly of small size. Both males and females of Nereis lim- 

 bata (p. 318, Plate XI, fig. 51, male) were often found among the barnacles 

 and ascidians on the piles of the wharves at Wood's Hole, but the males 

 were the most abundant, while the reverse was the case with those dug- 

 out of the sand and gravel on the shores. 



Numerous other Annelids were occasionally met with among the ascid- 

 ians and algre. Among these were Polycirrus eximius, (p. 320, Plate 

 XVI, fig. 85;) Podarke obscura V., (p. 319, Plate XII, fig. 61;) a Pliyl- 

 lodoce, &c. Two Nemerteans were also common; one of these was an 

 olive-green species, with alight dorsal stripe, belonging probably to the 

 genus Cerebratulus, but it was not carefully studied ; the second was 

 Polinia glutinosa, (p. 324, Plate XIX, fig 97.) 



Of Gastropod mollusks quite a number of species occur on the piles 

 of wharves, and some of them in great abundance, especially the smaller 

 kinds which live among the hydroids and conferva?. The most abun- 



