416 REPORT OF^DMMISSIONER OF FISH AND FISHERIES. 



bottom, and the same tube-dwelling species can attach themselves to 

 stones and shells just as well as to rocks. Most of the additional species 

 are burrowing kinds, and some of them probably inhabited patches of 

 mud or sand. Among the more interesting species are Nephthys hucera, 

 (Plate XII, fig. 58 ;) Anthostoma acuUnn V., a new species ; Scolecolepis 

 cirrata, new to the American coast ; Scalihregma hrevicauda V., a very 

 interesting new species ; Cirratulus tenuis V., a new species ; Ampha- 

 rete setosa Y., also a newsi)ecies ; Serpula dianthus V., (p. 322.) Several 

 rare or undescribed species were also met with that have not yet been 

 fully identified. Among these were a peculiar sjiecies of Nereis ; a large 

 Anthostoma ; a young PoJydora ; an apparently nndescribed species of 

 Samytlia ; a species of Uuchone, perhaps identical with ?J. elegans V. ; 

 the calcareous tubes of a small worm, perhaps a Yermilia, which have 

 two carina on the upper side. 



Two species of Sipunculoids occurred, one of which is probably un- 

 described. The other is the Pliascolosoma cccmentarium, (Plate XYIII, 

 fig. 92,) a species very common on all the northern coasts of New Eng- 

 land in deep water. This worm takes possession of a dead shell of some 

 small Gastropod, like the hermit-crabs, but as the aperture is always 

 too large for the passage of its body, it fills up the space around it with 

 a very hard and durable cement, composed of mud and sand united to- 

 gether by a secretion from the animal, leaving only a small, round open- 

 ing, through which the worm can extend the anterior part of its body to 

 the distance of one or two inches, and into which it can entirely with- 

 draw at will. It thus lives permanently in its borrowed shell, dragging it 

 about wherever it wishes to go, by the powerful contractions of its body, 

 which can be extended in all directions and is very changeable in form. 

 When fully extended the forward or retractile part is long and slender, 

 and furnished close to the end with a circle of small, slender tentacles, 

 which surround the mouth ; there is a band of minute spinules just 

 back of the tentacles ; the anal orifice is at the base of the retractile 

 part ; the region posterior to this has a firmer and more granulous skin, 

 and is furnished toward the posterior end with a broad band of scat- 

 tered, blackish, acute, recurved spinules, more or less triangular in 

 form, which evidently aid it in retaining its position in the shell. As it 

 grows too large for its habitation, instead of changing it for a larger 

 shell, as the hermit-crabs do, it gradually extends its tube outward be- 

 yond the aperture by adding new materials to it. Some of the fishes 

 often suddenly cut short this labor by swallowing the worm, shell and all. 



In July the common squids, Loligo Pealii, (Plate XX, figs. 102-105,) were 

 taken in considerable numbers by means of the trawl, on gravelly and 

 shelly bottoms off" Falmouth, and with them large quantities of the eggs 

 contained in large bunches or groups of long, gelatinous capsules. 

 They were apparently spawning at that time. 



Although the Gastropod moUusks are seldom xevy numerous at any 

 particular spot on these bottoms, yet a pretty largeuumber of species 



