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Show 1906.] OF SOUTHERN INDIA AND CEYLON. 655 Bergh says (Siboga, I. c.) that only Th. maculigera, Th. carinata, Th. tristis, and Th. hilaris can be included in the genus with certainty, though it is noticeable that he originally (Semper's Beisen, xvii. 1890, p. 913) marked Th. carinata with a query. Th. dubia and Th. pallida seem to conform fairly well to the generic diagnosis, though in the descriptions of the dorsal surface it is very difficult to know exactly what is meant by Zotten, Knotchen, and similar terms. Th. ? clandestine B. is smooth and the external teeth are not denticulate. Th. ladislavii was described by von Ihering (" Nudib. der brazil. Kiiste," in Mai. Jahrb. xiii. 1866, p. 234) as Etidoris, but Bergh in his 1 System ' regarded this genus as a synonym of Thordisa. The validity of the genus Etidoris may be doubted, but, as von Ihering remarks, the animal described by him comes near to Archidoris. It is tuberculate ; the tentacles are thick and grooved, and the rhachis of the radula bears thickenings. It differs from Archidoris only in having the outermost teeth denticulate. Boris millegrana was described briefly by Alder and Hancock (Monogr. pt. vii., Appendix, p. i). Yon Ihering (I. c. p. 238) created for it the genus Aporodoris, regarded by Bergh in his ‘ System' (p. 1098) as a synonym of Thordisa, but in the Opistho-branchia of the ‘ Siboga' Expedition (p. 94) recognised again as a separate genus and provided with a second species, Aporodoris ? rubra. The genus remains very doubtful, but, so far as the descriptions permit one to judge, seems allied to Archidoris. Alder and Hancock do not hint at any affinity between their Boris millegrana and their Doris ( Thordisa) villosa. Thordisa caudata Farran has not a villous back, and is perhaps referable to Trippa. See below under Trippa luteola. Th. crosslandi is discussed below. The remarkable Doris lanuginosa* of Kelaart, which is " green and covered with short downy hair," is perhaps a Thordisa or Diaulula. T hordisa villosa (A. & H.). (A. &H. I.e. p. 119. Eliot, Proc.Zool. Soc. 1903, ii. p. 367-8. Cf. Thordisa maculigera Bergh, in Semper's Beisen, Heftxii. p. 540. Id., Danish Exped. to Siam: Opisthobranchia, p. 182.) Two specimens, labelled Doris villosa, are preserved in fair condition. They differ somewhat in appearance. One is larger and more leathery than the other, and its dorsal tubercles are hard and warty. The smaller specimen is softer and the back villous rather than warty, the dorsal tubercles bearing soft filaments. It still resembles Alder and Hancock's plate {I. c. pi. xxxiii. fig. 1), and I also have but little hesitation in referring it to the same species as the specimens from Zanzibar described by me {I. c.) as Thordisa villosa. Further, it seems to me almost certain that the species, as * No drawing of this species was found. P r o c . Z o o l . S o c .-1906, No. XLIV. 44 |
