ANATOMY OF TUE OPUIDIA. 425 



of each being 10 mm. The quadripenis is calyculate, and the 

 cells are arranged in seven rows that trend obliquely forward 

 frotn the sulcus. The distal half of the body of the hemipenis is 

 spinous : opposite to the sulcus there is a septal fold. The 

 proximal half is plicate. At the border of the spinous area and 

 close to the sulcus there are two round, flat-topped, and gristle- 

 like papillaj ; these are closely set and one is distal to the other. 

 The sulcus is divided at a point 12 mm. from the base, this is 

 well within the plicate area. 



Mr. Rosen * writes that the hypapophyses are absent from the 

 posterior vertebrae in H. modestus Giinther and H. leopardmus 

 Schlegel. In this species they are well developed throughout, 

 one occurring even on the last dorsal vertebra. 



Cydoconts lineatus Reinhardt. — The hemipenis is of extreme 

 length and slenderness, being 38 mm. long and 2 mm. in diameter. 

 It is not divided and the sulcus is simple. The base for the 

 distance of 4 mm. is plicate ; the remainder of the organ, even 

 to the tip, is spinous. Towards the tip there are three slightly 

 elevated longitudinal ridges, one 8 mm., the others 5 mm. in 

 length. The spines are nearly uniform in size, being about 

 •3 mm. to '4 mm. long. Each is mounted on a broad fleshy base, 

 and is slightly recurved. When the walls are stretched the 

 spines are seen to be arranged in longitudinal series. 



Spilotes pullatus Linnseus. — The structure in this species is 

 one of the most complicated recorded. The total length of the 

 hemipenis from the base to the insertion of the retractor muscle 

 is 77 mm. The organ and sulcus spermaticus are undivided. 

 From the base to the 20 mm. point are longitudinal plications ; 

 the folds are thick, at first straight, later becoming wavy. From 

 the 20 mm. to the 38 mm. point it is densely beset with stout,- 

 blunt spines, each of which is about 2-5 mm. long. From the 

 38 mm. to the 54 mm. point on each side of the sulcus are rows 

 of flounces, these trend obliquely forward and acquire partitions 

 which convert them into rows of calycvili ; the cells of these 

 calyculi increase rapidly in size, the largest being situated 

 opposite to the sulcus. On each side of the sulcus at the 60 mm. 

 point are two thick flaps 10 mm. long ; these are in the longi- 

 tudinal plane, hang free in the lumen of the organ, and ai-e 

 covered with small regular ruches. Between one of these flaps 

 and the sulcus there is a thin membraneous septum 20 mm. long, 

 parallel to the sulcus, and hanging free in the lumen. Towards 

 the extremity of the organ the calyculi change to ii-regular 

 flounces ; these in tru-n are converted at the extreme tip into 

 minute frills. 



United States Fislieries Steamer 'Albatross ', 

 Sausalito, California, April 1st, 1913. 



* Ann. Nat. Hist. (7) xv. 1S06, pp. 170-171, fig. 1, 



