NEAY PEKIDIXIACE^. FROM THE ATLANTIC. 323 



CERATIE^. 



Ceratitjm, Schrank. 



The species of this well-marked genus were present in every observation except two. 

 C. Tripos, a species subdivided hj some authorities, was present, in one form or other, 

 in almost every gathering throughout the year from home waters to Colon, and is equally 

 steady in the single series of observations down the coast of Brazil. C. Furca, C. Furca, 

 var. baltlca, C. Fusus, and C. Candelabi'um appear throughout the records. C. Limulus 

 ranges from the Equator to about lat. 41° N., so far as our gatherings show^ its distri- 

 bution. C. gravidum^ a rarer species, and one of quite aberrant form, has much the 

 same range as C. Limulus, reaching lat. 38° IN". C. digitatum occurred twice only, 

 viz., in lat. 16° to 17 N., long. 68 to 69'' W. A very distinct new species, which we 

 have named C. hiconicum, occurred only once in lat. 35^ 20' N., long. 37 20' W. 



C. BICONICUM, sp. n. Body divided into two nearly equal limbs, widest at the girdle, 



each limb conical in shape, and the whole (including girdle) covered with fine 



punctate markings, streaks free from markings running lengthwise ; ends of girdle 



slightly oblique ; distal limb blunt at apex, proximal limb acuminate with irregular 



elongate foraminal area, and a thin membranous projecting flange near the foramen. 



(PL XXVII.figs. 4ia,b,c.) 



The nearest ally of this species is clearly C Fusus, which is much more elongate and 



thinner in proportion, and possesses a trace of a third limb near the girdle. There is no 



definite appearance of separate plates in the structure of the limbs or girdle. But for 



its resemblance to C. Fusus there would have been a difficulty in assigning C. biconici(/m 



to this genus, of which it is decidedly the simplest of its varied forms. 



The variations in the species of Ceratimn are noteworthy from the fact that it would 

 be almost possible to demonstrate a linear series of forms connecting C. hiconicum, 

 through C. Fusus, C. Furca, C. Candelabrum, and C. Tripos, with C. Limulus % 

 C, digitatum and C. gravidum being divergent. 



GoNYATJLAX, Dies. 



Gonyaulax birostris and G. 'poly gramma appear from our records to have a fairly wide 

 distribution in the Atlantic, the latter ranging from lat. 1 X. to lat. 42 X., and the 

 former being both tropical and temperate. Stein gives both as coming from the *' South 

 Sea." In addition to these species we have observed three others, all new. 



G. TuEBYNEi, sp. n. Body approximately ovate, divided into two nearly equal limbs by 

 the girdle, all its plates covered with punctate markings ; proximal limb composed 

 of one row of numerous narrow, elongate, mostly four-sided plates, the arrangement 

 of the plates irregular in the region of the foramen ; distal limb composed of two 

 rows of similar plates, those adjacent to the girdle being much larger than the 

 others. (PL XXVIII. figs. 4 a, h.) 



3b2 



