136 NOT ARCH US. 



Section Notarchus Cuv., s. sir. 



In the typical species of Notarchus the body is very plump and 

 not excessively elongated or slender at the two ends ; there are no 

 distinct labial processes ; the sole is extremely narrow ; and the in- 

 tegument bears conic warts, often more or less branching, but not 

 forming long, finely cut arborescent processes as in Aclesia. The 

 typical forms are N. indicus and N. punctatus. Some other small 

 species with lengthened extremities and smoother integument, such 

 as N. nudatus and N. citrinus probably belong here also ; while N. 

 ocellatus and N. polyomma are still very imperfectly known. 



N. INDICUS Schweigger. PI. 40, figs. 14, 15, 16 ; pi. 61, figs. 56, 57, 



58. 



Length 3-4j, breadth 2, alt. 2'3 cm. Head about one-third as 

 wide as body. Anterior tentacles stumpy, auriculate ; rhinophores 

 somewhat longer, excavated and auriculate ; mouth a longitudinal 

 slit ; eyes placed laterally before the rhinophores. Foot obtuse in 

 front, with two lobes, generally running out acutely. Sole with a 

 median longitudinal furrow. Body as if inflated, having the dor- 

 sal opening somewhat in front of the middle, the pleuropodial lobes 

 capable of being overlapped across it ; when separated widely they 

 raise up like a lid (fig. 14). Through this opening water is drawn 

 to the gills, and rhythmically (every 5 seconds) expelled again. 

 The conic elevations on the back and sides can be depressed. 

 Color transparent yellowish-white, marbled and punctate with 

 brownish-yellow or yellowish-brown. Many specimens are green- 

 ish-gray with olive-green flecks. Sole bluish, without markings. 

 Entire upper surface punctate with white, most densely so on the 

 conic protuberances, which are clear yellow in many specimens. 



Mauritius, in about 2 metres. 



Notarchus ...... CUVIER, Regne Anim. ii, 1817, p. 398, 



pi. 11, f. 1. N.indieus SCHWEIGGER, Handbuch derNaturgeschichte 

 der skelettlosen ungegliederten Thiere, 1820, p. 745 (based solely on 

 Cuvier's work cited above). MARTENS in Mobius' Beitr. zur Meeres- 

 fauna Maurit., p. 307, pi. 21, f. 4.N. cuvieri BLAINV., Diet. Sc. Nat., 

 xxxv, p. 101 ; Man.de Malacol., p. 473, pi. 43, f. 7 (1825). Aplysia 

 gelatinosa RANG, Hist. Nat. Aplys., p. 70, pi. 23, f. 1-5. QUOY & 

 GAIM., Zool. Astrol., p. 312, pi. 24, f. 3, 4. DESK., Traite Elem. 

 onchyl., pi. 92, f. 8-10. 



