184 20 



the riglit from the fore end of the gland, formed a not long grayish ampulla. The 

 ompressed, yellowish anterior genital mass had a length of 4°™; the mucous-albuminous 

 gland was small; the seminal bladders as usual (fig. 21). The seminal duct was not long; 

 it consisted as usual of a prostatic and a muscular part; the penis had a length of l'5 mm , 

 the greater part of its cavity was occupied by the unarmed glans of a length of l mm , 

 through which the continuation of the seminal duct ran to the point, somewhat wider in 

 the latter part. 



The form here examined was Thordisa maeuligera\ if, as may be possible, it 

 should turn out to be identical with the Doris villosa of Alder and Hancock, it will have 

 to assume the latter specific name. 



Dr. Mortensen took somewhat later at Koh Mesan on stony bottom at a depth of 

 10 — 15 fathoms another specimen, somewhat smaller, and with the larger marginal spots 

 more black. 



Chroinodoris, Ald. et Hamc. 



Cliromodoris histrio, Bgh. 



R. Bergh, neue Nacktschnecken der Südsee. IV. Journ. d. Mus. Godefl'roy. Heft XIV. 1878. p. 8—9. Taf. I, 

 Fig. 9-12; Taf. III, Fig. 10—14. 



PI. II, Figs. 22—24. 



Of this form two specimens were taken on March 9 th 1900, at the west coast of 

 Koh Chang, on old coral blocks, at a depth of one fathom. 



These specimens, when living, had a length of li mm . The ground colour was 

 transparent whitish, and so was also the colour of the rhinophores and the gill; the mantle 

 edge was yellow with longish violet spots; on the back two series of roundish violet spots 

 were seen, and anteriorly further a short median series. 



The specimens kept in spirit have a length of 5 — 6 mm , by a breadth of S™ 31 , and 

 a height of 2 mm . The colour was generally yellowish white; no traces of spots were found. 



The form was as usual. The rather posteriorly situated gill consisted of 7 — 8 

 leaves ; the anal papilla was subcentral. 



The central nervous system was as usual. The short-stalked eyes of a short-oval 

 form had a length of O'lO™ 11 ; the otocysts (stalocysts) of a diameter of 006 mm were closely 

 filled with otoconia of a diameter of up to 001 ^ mm . 



Around the outer mouth a strong glandular layer was found. The bulb us 

 pharyngeus had a length of l mm , the radula sheath projected somewhat posteriorly. 



