Orthocera. MOLLUSCA. CEPHALOPODA. 237 



three conspicuous globose articulations at the larger end, the 

 remaining joints being scarcely visible. 



N. sub. Mont. Test. Brit. 198, t. vi. f. 5 — From Sandwich, Mr Boys. 

 Length T T 5 th of an inch ; aperture a small produced syphon. A variety 

 was found by Mr Boys " having ten distinct articulations ; the extreme one 

 at the smaller end longer than any of the others, except the anterior one, in 

 which the aperture is placed." 



36. O. legumen.-— Compressed with oblique septa. 



N. rectus, geniculis depressis, Walk. Test. Min. t. hi. f. 74. N. Fig — 

 Mont. Test. Brit. Supp. 82. t. xix. f. G — Coast of Kent and Devon. 



Subarcuated, -J th of an inch, nearly of equal size, ends rounded. The an- 

 terior end surrounded by an oblique ridge, above which rises an obtuse sy- 

 phon, with a considerable aperture near the concave side. 



How far these species possess claims to continue in the genus Orthocera, 

 I have not been able to determine, as, in the course of numerous microscopi- 

 cal examinations of shell-sand from different parts of the Scottish coast, I 

 have not as yet detected a single individual of any of the species here no- 

 ticed. The existence of a continuous syphon would alone entitle them to 

 remain in this genus, otherwise they would belong to the genus Nodosaria 

 of Lamark, in which genus the three following species might be included, 

 though their history is at present involved in considerable obscurity. Their 

 multilocular character was first pointed out to me (in the case of the imper- 

 forata) by Mr Miller, the learned author of the Treatise on Crinoid Animals. 

 At present, however, I shall retain them in the genus Orthocera, and give 

 their characters from a single chamber, as the shells, entire, have not as yet 

 been met with. 



37. O. imperforata. — Chamber cylindrie, subarcuated, and 



slightly striated transversely. 



Dentale apice imperforata transversaliter substriata, Walk. Test. Min. 

 t. i. f. 15 Dentalium imp. Mont. Brit. 49(5 — On the English coasts. 



Length of the chamber |th of an inch ; aperture round, a little contracted 

 at the margin, the opposite end closed, truncated and furnished with a small 

 protuberance. 



38. O. Trachea. — Chamber subcylindric, and regularly an- 



nulated. 



Dent. Trachea, Mont. Test. Brit. p. 497, t. xiv. f. 10 — On the English 

 and Scottish coasts. 



Length about |th of an inch, and the diameter about ^d of its length. Co- 

 lour white. Rings regular, close set, sharp in a young specimen, but round- 

 ed in a larger one in which those near the mouth are largest, and the whole 

 are crossed by obsolete longitudinal ridges. It tapers little. The extremi- 

 ty is truncated with a raised acute margin, with a lateral tubercle on the disc, 

 the place of the syphon. 



39. O. glabra. — Chamber cylindrical, smooth, and glossy. 



Dent, glabrum, Mont. Test. Brit. 497 — Caecum glabrum, Flem. Edin. 



Encyc. vii. 67, t. cciv. f. 7- — English and Scottish coasts. 



The length of the chamber is about a line, and its diameter about ^th of 



its length. It is cylindrical, smooth, glossy, and transparent, the extremity 



hemispherical and submai'ginated. A variety of this shell, from Zetland, ta- 



