64 
THE VOYAGE OF H.M.S. CHALLENGER. 
(fig. 20) ; behind they are rather smaller, hardly exceeding ‘1 mm. in length (fig. 21). 
Their base of attachment is of a rounded triangular form, from which the spine arises 
more or less obliquely (fig. 22) ; the spinal portion is awl-shaped, and is more usually 
curved than straight ; occasionally abnormal forms arise (fig. 22), by the division of one or 
the fusion of the neighbouring spines. The axis of the basal portion of the larger spines 
is finely granulate, sometimes it is granulate through a larger extent (fig. 22). The 
white mucous gland with its fine windings forms the right portion of the anterior genital 
mass; on the hind portion of its left side is the clear yolk-yellowish albuminiparous 
gland ; the duct of the mucous gland has the usual strong longitudinal fold. 
This species differs in the armature of the tongue from the two other species which 
the genus contains ; these have three large lateral teeth, while this species has only two ; 
it has also a smaller number of outer teeth (five or six) than the others (eighteen or thirty- 
five). There are also some essential differences in the details of the generative system. 
Sub-family 2. Dorididse Cryptobranehiatee. 
Chromodoris, Alder and Hancock. 
Chromodoris , Alder and Hancock, Monogr. Brit. Nudibr. Moll., pt. vii., 1855, p. xvii. 
„ Bergh, Neue Nacktschnecken der Siidsee, III., Journ. d. Mus. Godeffroy, Heft 
viii., 1875, pp. 72-82; Heft xiv., 1878, pp. 1-50. 
,, idem, Untersuch. d. Chromodoris elegans u. villafranca, Malacozool. Blatter, 
Bd. xxv., 1878, pp. 1—36. 
„ idem, Neue Chromodoriden, Malacozool Blatter N.F., Bd. i., 1879, pp. 87-116. 
„ idem, Malacolog. Untersuch. (in Semper, Reisen im Archip. d. Philipp. Th. II. 
Bd. ii. ), Heft xi., 1877, pp. 464-494; Supplementheft i., 1880, pp. 14-27 ; 
Heft ii., 1881, pp. 81-85. 
,, idem, Beitr. zur Kenntn. d. japan. Nudibr. II. ; Verhandl. d. k. k. zool.-bot. 
Gesellsch. Wien, Bd, xxxi., 1881, pp. 219-222. 
,, H. v. Jbering, Beitr. zur Kenntn. d. Nudibr. d. Mittelmeeres, Malacozool. Blatter, 
N.F., Bd. ii., 1880, pp. 1-56; Taf. i.-iii. 
Forma corporis fere ut in Gfoniodoridibus, sed colores hilares, ssepe magnifici, ut 
plurimum striatnvel maculati. Branchia (retractilis) foliis simpliciter pinnatis. 
Armatura labialis e hamulis minutis confertis composita. Radnla rhachide nuda, 
pleuris multidentatis. Dentes hamati, primi utroque latere hami denticulati, reliqui 
externo solum; extimi humiles, apice denticulati. — Penis inermis. 
The genus Chromodoris was first established, though on insufficient grounds, in 
1854, by Alder and Hancock. 1 Ten years later the same authors 2 gave a more accurate 
1 Alder and Hancock, Monogr. Brit. Nudibr. Moll., pt. vi., 1854, Fam. 1, pi. xvii., Gen. 2 ( Goniodoris , F.). 
2 Alder and Hancock, Notice of a collection of Nudibranchiate Mollusca made in India, Trans. Zool. Soc. Land., 
vol. v., part 3, 1864, p. 123. 
