2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 9I 



19-26x3-3.5 (4)/x (probably penicilli). Spirocoridae (spirocysts) of 

 the tentacles 22-50 x about 2.5-7JU,. 



Color in alcohol: Scapus brown, papillae at their apex uncolored. 

 Size: Length of the body 1.5 cm, largest breadth 0.45 cm, length of 

 the tentacles about 0.3-0.4 cm. 



Holotype.— U.S. ISIM. no. 43238. 



Occurrence. — Station 100, northeast of Puerto Rico (lat. i8°4o'i5" 

 N., long. 64°5o'i5" W.) ; 150 fathoms; i specimen. 



The single specimen was not well preserved. The scapus had burst 

 in some places, with ejected filaments ; probably two tentacles were 

 lost ; the actinopharynx was evaginated ; and the pennons of the 



Fig. I. — Halcampogeton papillosus. 

 A piece of the scapus with two rows 

 of papillae. 



mesenteries were mostly loosened from the parietal muscles. I think, 

 however, that the description here given is in the main correct. 



The column is divisible into three regions, a rounded physa, a long 

 scapus, and a short, thin part, capitulum (or possibly scapulus). The 

 scapus is provided with 12 rows of very distinct and rather high but 

 solid papillae (fig. i), diminishing in size proximally. The ends of 

 these papillae are flat and broad and their ectoderm considerably 

 higher and of other structure than that of the other parts of the scapus. 

 The apex contains mainly gland cells and rather numerous but very 

 large nematocysts and is not pigmented ; the other parts of the scapus- 

 ectoderm are provided with a brownish pigment and exceptionally 

 few but smaller nematocysts. I am not sure that the nematocysts I 

 have found in the macerated preparations really belong to the scapus. 

 The mesogloea of the scapus is thick, especially in the papillae; in the 

 capitulum, thin. There is no sphincter. The tentacles were 10, but as 



