{22 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [416] 
bottom, and the same tube-dwelling species can attach themselves to 
stones and shells just as well as torocks. 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 bucera, 
(Plate XII, fig. 585) Anthostoma acutum V.,a new species ; Scolecolepis 
cirrata, new to the American coast; Scalibregma brevicauda V., a very 
interesting new species; Cirratulus tenuis V., a new species ; Ampha- 
rete setosa V., also a new species ; 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 species of Nereis; a large 
Anthostoma ; a young Polydora ; an apparently undescribed species of 
Samytha ; a species of Huchone, perhaps identical with FE. elegans V.; 
the calcareous tubes of a small worm, perhaps a Vermilia, which have 
two carina on the upper side. 
Two species of Sipunculoids occurred, one of which is probate un- 
described. The other is the aieetelosom' ceementarium, (Plate XVIII, 
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. Itthus 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 seat- 
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 mollusks are seldom very numerous at any 
particular spot on these bottoms, yet a pretty large number of species 
