REPOKT ON THE GASTEROPODA. 335- 



65. Pleurotoma {Pleurotomella) brychia, 1 Watson (PI. XIX. fig. 4). 



Pleurotoma (Pleurotomella) brychia, Watson, Prelim. Report, pt. 9, Journ. Linn. Soc. Lond., vol. xv. 



p. 451. 



Station 106. August 26, 1873. Lat. 1° 47' N., long. 24° 26' W. Mid-Atlantic. 

 1850 fathoms. Globigerina ooze. Bottom temperature 36° - 6. 



Animal. — In colour pale buff, with a greenish liver. The mantle is prominent, thin, 

 made up of separate, but connected, threads like a fringe, with a denticulated inargiu. 

 From within it to the left a great fold of flesh projects, whose drawn-together edges form 

 the anterior siphon ; this fold is an extension of the inner side of the mantle close withiD 

 its edge, which edge expands into a flap to enclose this siphon. On the right the mantle 

 is drawn back and expanded, so as to form an imperfect open channel corresponding to 

 the sinus of the outer lip. The body is rather small, cylindrical, protracted into a strong, 

 rounded, abruptly truncate snout, which is probably long when not contracted by the 

 spirit. On either side of the snout, and rather below the middle of its horizontal line, 

 project the tentacles, which are short, cylindrical, and blunt, and have no eyes at any part, 

 either of their base or on their length. The foot is large, being broad and flat, but not 

 high ; in front it is broad and square, with projecting rounded corners ; behind it is long 

 and pointed. There is no branchial plume ; but on the under surface of the mantle is a 

 strong central line with long pectinated fringes extending from it on either side. The 

 cloacal duct does not open in the body, but runs out on the right side in the mantle to a 

 large, longish, thickened nipple, which corresponds with the sinus of the shell. This duct 

 was full of hard oval green pellets. Mr John Murray, Director of the Challenger 

 Commission, kindly examined these for me, and writes : — " In the little pellets I find 

 Coccoliths, small Globigerinas, Pulvinulinas, and their broken fragments, Diatoms, Poly- 

 cistinas, Challengerias, fragments of a Crustacean, and setae of an Annelid." Operculum 

 none. 



Shell. — Very short and broad, biconical, subscalar, angulated, very thin, obsoletely 

 ribbed, with spiral threads, and having a longish, lop-sided, small-pointed snout. Sculp- 

 ture : Longitudinals — on the penultimate whorl there are about 20 short, scarcely oblique, 

 small, rounded, little prominent ribs, with shallow rounded furrows between of a like 

 breadth ; they only occupy the lower half of the whorls, extending to the inferior suture, 

 but not at all to the shoulder ; they diminish rapidly in number up the spire. On the 

 body-whorl they appear only as oblique and slightly elongated tubercles, which coincide 

 entirely in direction with the lines of growth. These are fine, close-set, and hair-like : 

 below the suture they are straight and irregular, forming on the upper whorls infrasutural 

 crenulations ; on the body-whorl they rise into slight undulations in prolongation of the 



1 ftu^/oj, from the depths. 



