OPISTHOBRANCHIATE MOLLUSCA FROM MONTEREY BAY. 147 



l)ase, the fn^e end about 0.05 mm., with a total length of about 0.270 iiiiii., l)luut anil y.iiZgeA as though 

 Ijroken off, its proximal portion extending acro.'^.s the whole band ami interrupting the continuity of 

 the hooks below (pi. xx, fig. 82). 



Radula narrow, deeply grooved, the teeth in 24-2S rows, the last two of which are rudiiucntary. 

 The oldest teeth colorless, those toward the posterior end of the radula light yellow. 



Rhai'his very narrow, naked. First pleural tooth (pi. xx, flg. 84) large, upright, compressed, its 

 base quadrangular in lateral outline and overlapping the outer anterior margin of the first pleural of 

 tlie following row. Lower portion of the base strongly thickened, upon its upper posterior border a 

 scjuarish thickened shoulder directed obliquely upward. Height of base about 0.192 mm., its length 

 0.0B6 mm. The anterior portion of the base is prolonged upward into a strong, slightly curved hook 

 al)out 0.150 mm. in length, upon the inner l)order of which is a series of 14-19 denticles, the longest 

 being 0.012 mm. in length. The remaining pleune, 6-7 in number, are .=mall, borne obliquely on the 

 radula, and decrease regularly in size outward. The first of the outer plates (pi. xx, figs. 85, 86) are 

 depressed, flattened above, bluntly pointed behind and have a thin, keel-like plate below, the general 

 shape being somewhat similar to that of the first pleural tooth; the outermost ones are reduced to 

 mere flattened plates (pi. xx, flg. 87). 



The anterior genital mass is small, plano-convex, its flattened face directed inward and upward, 

 somewhat oval in shape, with a long diameter of about 4 mm. The hermaphrodite duct is sliort 

 and very narrow, dilating almost immediately into its whitish ampulla (pi. xx, fig. 88, Ji. aiiip.) of 

 about 0.5 nun. diameter, with a length of about 6 nnn. The ampulla describes an S-fornied loop 

 u]5on the plane face of the anterior genital mass, its lower turn coursing forward and upward along 

 the anterior margin of the nidamental gland, entering into it and dividing into the oviduct and the 

 sjiermatic duct. The uterine duct (pi. xx,fig. 88, 88n, it. d.), emerging from the gland, narrows rapidly 

 in passing upward to the superior border of the genital mass, receives the short duct of the pear- 

 shaped spermatocyst, 0.4 mm. long by 0.3 mm. wide (pi. .x.x, fig. 88o, up. c. ), and passes into the sper- 

 uuitotheca. The spermatotheca (pi. xx, fig. 88, 88o, sp. th.) is spherical, about 1 mm. in diameter, 

 with a very short common duct receiving the uterine duct and the vaginal duct. The latter (fig. 88, 

 ssrt, vug.), together with the vagina, is not more than 6 mm. long, much shorter than in any other 

 species of this genus yet described, its diameter gradually increasing from 0.3 mm. to O.K mm. and 

 passing without definite boundary into the vagina. 



The spermatic duct is very long and much convoluted, its loops lying at the antericir iKmUv nf 

 tlie genital mass. The first 9 nun. of its length are closely bound down to the genital ma.-^s by con- 

 nective tissue, have an average diameter of 0.8 mm., and are sharply marked off from the succeeding 

 slenderer portion, which describes a large loop free from close connection with the remainder of the 

 organs. This muscular portion is 0.2 mm. in diameter with a length of 9 mm., the total length of the 

 whole duct thus being 18 mm. It enlarges rapidly at its distal end and passes into the thicker cylindro- 

 conical penis, 3 mm. in length by 1 mm. in average diameter. In the specimens dissected a part of 

 the distal end of the glans was missing, and hence the armature of hooks could not be made out 

 satisfactorily. 



Haliitat: Dredged off hard sandy lintt(,ini i?i abi.iut 10-20 meters depth near entrance to Monterey 

 Harbor. Twelve specimens were taken in two drcilge hauls in 1894, and an occasional specimen has 

 been dredged since then near the same locality. Type no. 181293, U. 8. National Museum. 



Genus 15. ANCULA Lov^n. 



.inciila LiivOn, liide.v Moll. Soaml., p. r,. 1.S4C,.— .\lder and Hancock, Monog. Brit. Xudibr., Ill, 1846, Fam. 1, pi. 2.5; VI, lSb4, 

 Fam. 1, pi. 17, fig. 7-8; VII, lSo5, pi. 4(>, Sup. flg. 22; Appendix 18,i,i, p. .wiii.— Meyer and Moebius. Fauna der 

 Kieler Buc-ht, I, 1865, p. 59.— G. O. Sars, Moll. reg. arct. Xorv.. 1878, p. 364.— Bergh, Bcitr. z. Jfonogr. der 

 Polyceraden, II, 1880, p. 3. System der Nudibr. Gasteropoden, 1892, p. 164. 



Body limaciform, smooth; scarcely any frontal veil; rhinophores nonretractile, with two anterior 

 linear basal appendages; branchial plumes 3, tripinnate, with several simple extrabranchial appen- 

 dages; head small, tentacles rather short, lobiform, somewhat flattened; foot narrow, rounded in front. 



Labial armature made up of rows of separate imbricated hooks. Radula narrow, the rhachis 

 naked; first pleural tooth large and broad, its inner margin denticulate, the remaining one much 

 smaller, subtriangular. Buccal crop sessile. 



Glans penis armed. 



