282 SIDNKY F. HARMER. 



the species occurs in encrusting, Hemescharan (of ''Sipho- 

 nellaform" — not to be confused with Siphonoporella, 

 Hincks) and Escharan growth, at a depth of 15 — 37 fathoms 

 off Florida. If all the specimens which I have referred to 

 S. magnilabris are correctly placed there, the species must 

 be regarded as a somewhat variable one. It is the only form 

 with A- shaped main sclerite in the b opercula in which the 

 cryptocyst of both a and b zooccia joins the basal wall at a 

 considerable distance from the distal wall. The large ex- 

 posure of the basal wall and the invisibility of the opening 

 of the tube, when seen from above, are characteristic marks 

 of this species, which is, moreover, peculiar in the possession 

 of well-developed submarginal teeth in the a opercula. 



The following description refers to the type-specimen (fig. 

 10) : — The edge is thin and sharply separated from the post- 

 oral shelf. This is but slightly developed, finely tubercular, 

 and may be vestigial proximally. The oral shelf is moderate in 

 B, narrower in a, where it is mostly smooth, and may be con- 

 spicuously denticulate near the base of the oral arch. The 

 condyles are much larger in b than in a. The oral arch is 

 much raised ; by the overlapping of the zooecia over their next 

 neighbours distally there is a large concave space in the 

 B zooecia, between the oral arch and shelf. The oral arch of 

 B is much larger tlian that of A, the shape corresponding 

 with that of the respective opercula. The cryptocyst is 

 sharply separated from the post-oral shelf (except, as in 

 most other species, at the distal corners of its horizontal 

 portion), descendiug steeply (without any angulation in the 

 type-specimen) into the cavity of the median process. This 

 is wider in a than in b ; it is moderately deep, its wide, 

 rather long floor being constituted by the convex roof of the 

 tube, whose opening is vertical and invisible from above. 

 The lateral recesses are commonly very asymmetrical, only 

 one meeting the basal wall, the floor of the other passing 

 into the lateral wall of its side. On examining the back of 

 the specimen this arrangement gives rise to the appearance 

 of fig. SI. The thick curved line rising from the left lateral 



