OCR Text |
Show 1880.] PROF. F. J. HELL ON THE TKMNOl'LEURID.E. 425 line of the interambulacral arese ; and though not so deep nor so wide as in T. toreumaticus, they extend almost to the base of the primary tubercles; on the other side of these tubercles there are narrower and shallower furrows; and in the middle line of the ambulacral areae there are deep sutural pits: all these depressions are much more distinct above the ambitus than they are on the actinal surface,in which point they offer a striking point of difference from T. reevesii. The test is by no means thin ; all the ocular plates are excluded from the anal area; the outermost, not the innermost, of the three tubercles on the interambulacral plates is the smallest. The following are the more important measurements :- Diameter. Gray's type.. 37 32 Height, 18 [48.6]1 16*3 [50] .bactinal area. 8 [21*6] 7*0 [21*8] Anal area. 3*5 [10*9] Actinostome. 10*5 [28*3] 10*2 [30*9] Spine. 10*52 In other words T. granulosus differs from T. reevesii (i. e. T. reynaudi) in the facts that:- i. The abactinal area is not large ; and the anal area is much smaller. ii. All the ocular plates are excluded from the anal area3. iii. There are sutural furrows and deeper angular pits. iv. The miliaries are much more numerously developed. v. There is no specially large anal plate. vi. The actinostome is a good deal smaller. These differences appear to me to be sufficient to justify us in regarding Gray's Toreumatica granulosa as a distinct species; it is, however, obviously enough a member of the genus Temnopleurus. The following is a table of the dimensions of T. reynaudi proper, the T. reevesii of Gray. i iii iv v vi Absolute diameter in millims. 7*1 7-5 10 10-5 21 35 Percentage value of Height. 465 42-6 42 476 42-8 Abactinal area. 38 40 31 3619 30-9 25-7 Anal area. 17 20 15 19 16*16 15*1 Actinostome. 40-8 40 33 33-3 33-3 31-4 As in the case of the preceding species, we m a y here note some 1 The numbers in brackets are the percentage results. 2 Greatest length measured. 3 Gray's type specimen has lost the abactinal plates ; but two specimens collected by Capt. St. John in the Corean seas are perfect. |