NEW PEEIDINIACE^ FROM THE ATLANTIC. 333 



describe, lat. 35 X. represents the farthest north of Hist loneis Fratwesccu ; lat. 31 N. 

 of two, viz. S. mghleii and H. Ilitchellana ; lat. 30° N. of U. Releiice ; lat. 29° N. of 

 S. Dolon; lat. 33^ N. of S. Para; lat. 2i° N. of M. dentata; and lat. 23° N. of 

 M, Milneri. It Avill he seen, therefore, that these additions to the genus are all, like 

 the species already known, confined to the warm Atlantic. On PI. XXXII. fig. 6 we 

 have figured JI. hiremis. Stein, a different form from Stein's, though clearly the same 

 species. In our specimens the funnel is of somewhat different shape and quite differently 

 marked, and the sail also differently marked. The latter variation occurs in most species. 

 Our records are rich in new species of this remarkable genus. 



HiSTiONEis Erancesc^, sp. n. Body irregularly globular, composed of proximal limb 



and girdle, slightly compressed laterally, pitted ; girdle broad, pitted, distal margin 



expanded into a large wide funnel with unbranched radiate nervation and entire edge, 



proximal margin forming a broad pitted collar, open on dorsal as well as on ventral 



side, one half continued dowm on ventral side to the sail, the division between end 



of collar and sail near foramen ; sail extending underneath the proximal limb along 



the junction of the two plates that form the limb, with straight, occasionally 



branching nervation (the nerves being fairly uniform in size), and pitted, especially 



near the body, with an entire margin bordered with parallel peripheral lines ; distal 



limb reduced to a small flat membrane at base of funnel. (PI. XXXII. fig. 3.) 



It ranges from lat. 35= 20' N. to lat. 14° to 16° N., long. 58° 32' W. It never occurs 



plentifully even though it has so wide a distribution, practically from the Azores to 



Barbados. 



It is chiefly on the characters afforded by this singularly beautiful species that the 

 generic distinction l)etw^een Stein's Ornitliocercus and Histioneis breaks do^ii. The 

 collar open on the dorsal side, with the other characters, brought this species into line 

 with our JBL. Para, H, hiremis^ Stein, &c. ; while, on the other hand, in describing it Ave 

 have to bear in mind the necessity of distinguishing it from H. magnifica, the original 

 type of Stein's Ornithocerciis. It may readily be distinguished from it by the collar 

 open on the dorsal side and by the whole character of the sail, which has no specially 

 stout nerves running down to thickened endings as in JS. magnified, but a close-set 

 uniform nervation, with pits near the body. 



H. Para, sp. n. Proximal limb from semi-globular to semi-oval in shape, very little if 

 at all compressed laterally, pitted, wdth a long, narrow, pointed, flat sail, sometimes 

 pitted near the point only (and in that case with a few transverse thickened bars), 

 decurrent to the extremity of limb or nearly so; girdle l:>road at the proximal 

 margin, pitted, the proximal margin expanded into a collar, unmarked, but 

 supported by a few upright thickened bars, open on both dorsal and ventral sides 

 but not decurrent to the sail, which, however, reaches its base ; distal mar^-in 

 expanded into a broad funnel with radiating nervation, the nerves unbranched 

 edge entire ; distal limb reduced to a flat membrane. (PI. XXXII. figs. 4 a, h, c.) 

 This species was at times fairly plentiful from 28° N. in the Atlantic to Panama in 



