12 



Polycheles typhlops, Heller. 



PL I, figs. 1-13. 



Polycheles typhlops, Heller, 1862. 

 Polycheles typhlops, Heller, 1863. 

 Polycheles typhlops, Carus, 1885. 

 Polycheles Doderleini, Riggio, 1885. 

 Pentacheles Hextii, Alcock, 1894. 

 Polycheles typhlops, Adensamer, 1898. 

 Pentacheles Hextii, Alcock, 1901. 

 Polycheles typhlops. Senna, 1903. 

 Polycheles typhlops, Bouvier, 1905 (a). 

 Polycheles typhlops, Bouvier, 1905 (b). 

 Polycheles typhlops, Kemp, 1912. 



The carapace is slightly shorter than the abdomen. Its" 

 dorsal surface is almost flat, and its lateral margins are very 

 slightly convex. The frontal margin considered as a whole is 

 slightly concave, and is divided into three lobes by the deep 

 sinus at each side, in which the fixed and immovable eyestalk 

 lies. The median lobe is bounded at either side by a strong 

 spine. In the centre is the rostrum, formed by a single sharp 

 spine pointing forwards and upwards. Below this there is a 

 broader and blunter process in the median line. The outer 

 border of each orbital sinus is furnished with three or four small 

 teeth, which are more distinct in the female than in the male. 

 At each antero-lateral angle of the carapace there is a strong 

 curved spine, and from this there runs backwards a line of teeth 

 along the lateral margin. These lateral spines decrease in size 

 towards the posterior end, and the series is divided into three 

 parts by the two branches of the cervical groove. The front 

 part has usually seven spines, the middle four or five, and the 

 hind part about twenty. The numbers however vary consider- 

 ably. Senna gives them as 6 or 7, 4, 14 to 18, and Carus 7, 5, 

 20 to 23. The two sides of the same specimen even may show 

 differences in the number of spines ; in one of the specimens 

 taken by the Helga the left side has 7, 5, 18, and the right, 8, 

 5, 20. The hind carapace margin is strongly concave, and is 

 composed of a strong bar, the two halves of which meet at an 

 obtuse angle in the centre. At this point there are two large 

 forward -pointing spines, and two smaller ones further down on 

 either side. The posterior extremities of this bar are firmly 

 buckled to the first abdominal segment. From the middle of 

 the hind margin to the rostrum there runs a raised carina along 

 the whole length of the carapace. It is broken only at one point, 

 where it is crossed by the cervical groove. It bears several dis- 

 tinct spines, some of which are double, and between these it is 



