562 PROCEEDINGS OF THE ACADEMY OF [July, 



the branchiae there is usiiall}- a narro\\' band of dull ])urplish-1:)rown on 

 the branchial bases and 3 zones of rich ]3\irplish-bro\vn on the basal 

 half of the branchiae, tlie lower two of which sometimes coalesce to 

 form a A^ery broad zone covering the entire occelated region. On the 

 alcoholic specimens this color very little involves the outer surface of 

 the stems, but is deep on their inner surfaces and the barbs. On one 

 specimen the barbs of the basal half of the branchine are also largeh^ 

 orange and the pigment of each eye extends as a narrow oblique line 

 in a proximal direction halfway across the outer surface of the stem. 



The tubes of this species occur, sometimes singly attached to stones, 

 sometimes in clumps of several wound among one another in an intri- 

 cate fashion and firmly united. They are thick, of cartilage-like con- 

 sistency after preservation and usually little encrusted with sand or 

 other foreign substances. In one case the attached surface of the tubes 

 is much infiltrated with calcareous matter. 



Specimens occur off Fort Rupert, Vancouver Island (station 4,202), 

 in 25-36 fathoms, on a bottom of gray sand ; in Icj' Strait (station 4.261), 

 in 10 fathoms, on a bottom of mud and rock; and at Afognak Island 

 (stations 4,269 and 4,270), in 14—19 fathoms, on a bottom of hard sand 

 with rocks. The last station yielded tlie largest specimens, among 

 them the type. 



Pseudopotamilla intermedia sp. nov. PL XXXVII, figs. 15 to 22. 



Of this well-marked species the type alone is known. This is a 

 female filled with eggs and having a total length of 58 mm., of which 

 the branchia3 are 3 mm. and the thorax 7 mm. The thorax is 2 mm. 

 and the anterior part of the abdomen 2.5 mm. wide. There are 158 

 somites, 10 (9 setigerous) of which are thoracic. 



Most noteworthy is the small size of the branchiae, the extreme length 

 of which is only 3 mm. The entire absence of pigment and the rela- 

 tively pale color of the eyes suggests the possibility of their being in 

 process of regeneration. The branchial ])ases are remarkal^ly small, 

 of soft texture, have the distal margin evenly transverse, the ventral 

 margin truncate and not at all elongated or spirally coiled, and the dor- 

 sal margin provided with a notched lappet as in P. brcvibrayichiaia, but 

 smaller and soft and meml^ranous instead of rigid. Each palpus bears 

 12 branchiae, including 2 or 3 rudimentary ventral ones. The longest 

 are only 3 times the height of the base, and only a little more than -J of 

 the length of the thorax. In arrangement they are strictly one-ranked, 

 and none is crowded into the interior. The stems are rather stout, 

 roimded on the external face and lack altogether marginal wings and 

 connecting membranes. The barl^s are two-ranked, distributed rather 



