MARINE INVERTEBRATA OF GRAND MAN AN. 17 



that on which the suckers are most developed. They never bury themselves, but 

 are found on the surface of the rocks, and sometimes in chinks or among large 

 pebbles. 



Thyonidium prodtjctum, St. Orcula punctata, Agass., Proc. Am. Acad., 1851, 

 (no descr.) Duasmodactyla producta, Ayres, 1. c, 244. This species is found in 

 deep water, but occurs most frequently under stones, or buried to a slight depth in 

 gravel near low-water mark. 



Duben and Koren give in their generic diagnosis of Thyonidium, "tentacula 10, 

 quibus interjacent totidem paria tentaculorum triplo breviorum," which character 

 is well marked in this species. In fact, if distinct, it is at least very closely allied 

 to their T. pellucidum. 



Chirodota l^vis, St. Holothuria laivis, 0. Fabr., ¥. G., 353. Sijnapta coriacea 

 Agass., Proc. Am. Acad., 1851, ii. 269. TrocMnus pallidus, Ayres, Bost. Proc, iv. 

 243. This species is fully and well described by Otho Fabricius, and his account 

 of its habits applies precisely to those of our species, as I have often observed at 

 Grand Manan. It lives in the stony mud of the shores of these islands, buried to 

 a depth of a few inches, usually in a horizontal position. It is found at low water, 

 but is most abundant at a depth of four or five fathoms. 



The genus D-ochinus of Ayres is synonymous with CJilrodota of Eschscholtz 

 (see Esch., Zoologischer Atlas ; also MiddendorlF, Sibirischer Reise, in which latter 

 work full anatomical figures are given) ; the Chirodota of Forbes (Brit. Starf., 239) 

 being a Synapta (see Duben and Koren, Ofvers. af Skand. Echinodermer, 323). 

 Our Chirodota arenata must, therefore, form the type of a new genus, for which I 

 would propose the name Caudina. It is well described by Mr. Ayres, in Bost. 

 Proc, iv. 143. Caudina arenata does not occur in the Bay of Fundy, notwith- 

 standing its abundance on every sandy shore in Massachusetts Bay. 



Huxley, in Dr. Sutherland's Journal of Penny's Voyage to Wellington Channel, 

 describes a Chirodota which must be closely allied to C. laivis; but, if his descrip- 

 tion be exact, it differs in the number of spokes in the calcareous wheels of the 

 skin. 



BRYOZOA. 



Tubulipora patina, Johnst., Brit. Zooph. The species which I consider iden- 

 tical with T. patina, notwithstanding some differences, is very common on our 

 whole coast. It is mostly found on seaweeds in shallow water. 



T. CRATES, St., n. s. Polypidom generally of large size, suborbicular, sometimes 

 irregularly lobed at the circumference. Cells very slender, curving upward, show- 

 ing a disposition to linear arrangement, and often rising in circles around cup- 

 shaped depressions, where the tallest (immature) ones have very minute or no 

 apertures. Color white. There is no distinct margin. Diameter often three- 

 fourths of an inch. Found encrusting Terehratuloi in deep water. 



