14-1 BULLETIN OF THE BUREAU OF FISHERIES. 



Pharyngeal bulb supplied on its upper surface with asessileor petiolated sucking crop (ingluvies). 

 Labial disk covered with simple cuticle or armed with a ring of hooks or mandibular plates. Radnla 

 more or less narrow; rhachis naked or occasionally with spurious teeth; pleurse usually with a sinj^'le 

 large hooked tooth, occasionally two hooked ones, and with usually few, sometimes many, external 

 teeth. 



Glans penis upually armed with a series of hooks. 



Genus 14 ACANTKODORIS Gray. 



Acanthodoris Gray, Fig. Moll. Animals, IV. IS-iO. p. 103. Guide Moll. Brit. Mus., 18.57, p 207.— Alder and Hancock, Mon. 

 Brit. Nudibr. Moll., VII, 1865, p. 43; Ap. p. xvii.— 6. O. Sars, Moll. Reg. Arct. Norvegia;, 1878, p. 308.— Bergh, 

 Gattungen nordischer Doriden, Arch. f. Naturgesch., XLV, 1, 1879, p. 3.56. Nudibr. Moll. North Pac, II. Proc. 

 Acad. Nat. Sci. Phila. 1880, p. 237. Monog. d. Polyceraden, III, Verb. d. k. k. zool.-bot. Gesch. Wien, XXXIII, 

 1883, p. 170. Malacol. Unters., H. XVII. 1890, p. 988. System der Nudibr. Gasteropoden, 1892, p. 1,58. 



Body soft, subdepressed; notfeum thickly covered with short villi; margin of rhinophore aper- 

 ture lobed; branchial plumes few, tripinnate, arranged in a circle; head wide, veliforin, tentacles 

 short, lobiform. 



Armature of labial disk of minute hooks, below with j)rpjecting thickenings of the cuticle. Radula 

 rather narrow; rhachis naked; first pleural tooth very large, hooked, external pleural teeth few (4-8), 

 smafler. Buccal crop connate with pharyngeal bulb. 



Glans penis armed; vagina very long. 



17. Acanthodoris hudsoni MacFarland. 



Acanthodoris hudsoni MacFarland, op. (it., p. 51. 



Body plump, highly arched, slightly higher and broader in front than behind, the jreneral body 

 outline oval. Dorsum soft, villous everywhere, covered l)y small, thickly set, bluntl_\' conical papilUe 

 (villi), but slightly retractile. Margin of mantle everywhere overlapping the foot except at tip of the 

 tail, its margin liroad and rather thick. 



General ground color of dorsum and ventral surface clear translucent, yellowish white, or pink- 

 ish, the papilla' and branchial plumes tipped with lemon yellow, the mantle edged with the same 

 color. 



Length of animal up to 35 mm., breadth up to 22 mm., and height 9 mm. 



Head (pi. xx, fig. 7.S) wide, veliform, the sides prolonged into broad, triangular, pointed tenta- 

 cles, a wide, rounded notch between them in the median anterior margin of the head. Moutli a small 

 longitudinal slit. 



Foot broad, rounded abruptly, and slightly concave in front, the sides very slightly tajiering 

 toward the posterior end, where it is less abruptly rounded to the lilunt tail. 



Rhinophores long, tapering, inclined forward, the clavus recurved and inclining slightly back- 

 ward. Perfoliate with about 24 leaves, the length of clavus and stalk nearly the same, about 5 mm., 

 the whole organ 10 mm. long with a basal diameter of 2 mm. Retractile into a low sheath, the mar- 

 gin of which bears numerous short papillce similar to those of the dorsum. 



Branchial plumes 5, bipinnate, nonretractile within sheath, widespreading, arranged in a circle 

 inclosing the an;il papilla and numerous slender papillae similar to those of the general dorsum. Anal 

 opening at the summit of a low blunt papilla, connate to the sides of which are 3-5 slender-pointed 

 processes forming ridgelike lateral elevations and extending beyond the summit. Pseudoperitoneum 

 sparsely sprinkled anteriorly with tine dark flecks. Blood gland elliptical, light colored, disk-like, 

 about 1 mm. long by 1.5 mm. wide and 0.5 mm. thick, lying transversely above the central nervous 

 system. 



Pharyngeal bulb 2 mm. long, 2.5 mm. high (including crop), and 1.3 mm. in width. The crop 

 conspicuous, hemispherical, with a narrow median longitudinal muscular band, the sides ridged with 

 muscular bands converging toward the under portion, it.s walls very thick. The radula sheath pro- 

 jecting behind and below for 0.5 mm. No conspicuous esophageal diverticulum at anterior end of 

 the esophagus as in A. hrminen from the same locality. 



