SYSTEMATIC REPORT 103 



Genus Amblyops G. O. Sars 

 1869 Amblyopsis G. O. Sars, p. 328. 

 1872 Amblyops G. O. Sars, vol. II, p. 3. 



Remarks. The chief difference between this genus and Psendomma is in the form of the eyes. In 

 both genera these are rudimentary and reduced to immovable, flat plates with no trace of visual 

 elements. In Pseadomma, they are fused along their inner margins to form a single thin oblong plate 

 covering the bases of the antennules and antennae. The anterior and lateral margins of this plate may 

 be entire or more or less serrulated. In Amblyops the two eyeplates are thicker and, although they 

 may lie very close together, they are always separate. Their margins are not serrulated, but the anterior 

 dorsal region may be adorned with very fine spinules or bristles. A more or less well-developed ocular 

 papilla is present on the dorsal surface of each eyeplate and, although there are no visual elements, 

 the plates may be diffused with a faint colour or have flecks of reddish pigment on the dorsal surface. 



In the past, six species have been referred to the genus Amblyops, A. abbreviata (M. Sars) 1869, 

 A. crozetii ( W.-Suhm) G. O. Sars, 1885 a, A. kempii (Holt and Tattersall), 1905, A. tenuicauda Tatter- 

 sall, 191 1 b, A. tatter salli Zimmer, 1914, and A. ohlinii W. M. Tattersall, 1951. These species fall 

 into two groups based on differences in the form of the antenna, which I consider to be of generic 

 significance. 



In A. crozetii and A. ohlinii the antennal scale is oval with its outer margin short and terminated by 

 a very strong tooth which has no supplementary tooth on its inner face. The apex is very long and 

 occupies nearly half the whole scale. The antennal peduncle is composed of three segments which 

 lie in the same plane and are articulated in the normal manner. In the other four species the outer 

 margin of the scale is very long and the strong spine which marks its distal end usually extends well 

 beyond the small apex. This spine usually bears one or two very small supplementary spines on its 

 inner face. An articulation marks off a very small distal segment of the apex. The antennal peduncle is 

 composed of four segments, the second very short and bent upward from the plane of the first. The 

 third segment is somewhat swollen and is articulated with the second on its ventral proximal surface 

 and is bent downward so that its proximal end overrides and almost covers the anterior end of the 

 second segment. 



In dorsal view the whole of the second segment may be covered and the peduncle appears to consist 

 of the normal three segments but in lateral view the articulation of the segments gives it a peculiar 

 distorted appearance as though the segments were dislocated. 



In his description of A. tenuicauda Tattersall (191 1, p. 44) states that the antennal peduncle is 

 composed of ' three joints roughly subequal '. I have re-examined specimens of the species from the 

 west of Ireland and find that in dorsal view the peduncle appears as described and figured by Tatter- 

 sall but in lateral view it can be seen that there are in fact four segments which are articulated as 

 described above. 



Three (and possibly four) new species are represented in the Discovery collection. Two of these, 

 A. durbani and A. antarctica, have the antennal scale and peduncle similar to that in A. abbreviata, 

 A. kempii, A. tenuicauda and A. tattersalli; the third has a scale and peduncle similar to that in 

 A. crozetii and A. ohlinii. I suggest that this second group might be placed in a new genus Amblyop- 

 soides and that the definition of the genus Amblyops as regards the antenna should be as follows: 

 Antennal scale long and usually narrow; unarmed outer margin terminated by a strong spine or tooth 

 (beyond which the small apex does not extend) which may be armed on its inner face with one or two 

 small supplementary teeth. Small distal suture present. Antennal peduncle composed of four seg- 

 ments. The second and third segments lie in different planes and are articulated, so that the proximal 



