20 ART. 2.— BASHFOED DEAN. 



innately equal length. Transverse muscles (branchial constrictors) 

 situated along a considerable space ventrad of the gill sacs. Aperture 

 of ductus œsophagœus somewhat larger than gill openings. (Cf. 

 Text-fig. 4, J, B). 

 (Species I) Stouli. Lockington, 1878, Am. Nat., p. 793. 



Twelve gills (variations from 10 to 15). External branchial 

 ducts short. Base of tongue muscles between fifth or six pair of 

 gills. Dental formula nr | ttt (variations from # 1 f- to ff | tt). Average 

 size of adult (based upon 100 specimens) 42 cm. Brownish purple, 

 with margins of branchial apertures and mucous pores white. 



Eggs average 20 in number, each (all lengths here given not 

 including filaments) about 23 mm. long by 8 mm. thick : anchor 

 filaments average about 45 at animal pole, 35 at vegetal. Operculum 

 almost invariably wanting near vegetal pole. 



Habitat, Coast of California. 



(2) Polylrema, Girard, 1854. Pro. Acad. Nat. Sei. Philo,., p. 199. 

 (=Le Gastrobranche dombey (non-binomial), Lacepede. 1798. Nat. 

 Hist. Pois. J, p. 531) : (=bishoffi, Schneider.) 



fen gills (variation to 14). External branchial ducts short. 

 Base of tongue muscles between seventh and eighth pair of gills 

 (Putnam). Dental formula varies (Ayers) from V" I "¥ *° t! I it- 

 Average size 45 cm. 



Eggs in single instance — probably of H. polytrema — 34 in number 

 (Plate), measuring about 22.5 by 9.5 mm. Filaments at either pole 

 about 80 and relatively long. Operculum common at vegetal pole. 



Habitat, Coast of Chili. 



(3) Okinoseana, nov. sp. 



Eight gills. External branchial ducts short. Base of tongue 

 between second or third pair of branchial sacs (allèrent artery divides 

 opposite seventh pair). Dental formula !«• | tt (tt ) tt in one speci- 



