Description of Genera and Species. 53 



Locality. — Cementstone Quarry, East Kilbride, Lanarkshire. 



Horizon. — Lower Limestones, (Scottish) Carboniferous Limestone Series. 



Collector. — -Mr. Andrew Patton. 



Systematic Position of the Perimecturiihe. — Whatever may be the ultimate system- 

 atic position assigned to the forms included in this family as the result of future 

 discoveries, there can be no doubt as to their forming a closely-connected natural group. 

 The size and form of their tails and tail fans, coupled with the fact that many of the 

 trunk segments are complete rings and comparatively free from each other, as well as 

 being only loosely covered by the carapace or left bare, and also the movable leaf-shaped 

 rostrum, naturally suggests affinities with the Squillids. These characters, however, 

 are shared by the modern Anaspides, the Lophogastrids, and one may also add to 

 these the Mysids. The occurrence of what are evidently breeding lamellte or brood 

 pouches in some of the species, the exopodites on the trunk legs, the wide sternites of 

 the trunk segments, the mode of flexing the trunk limbs, and the habit of bending 

 down the heads and carapace on dying, show conclusively that they are Schizopods. 

 The correspondence in number and position of the longitudinal keels both on the 

 carapace and the tail, in the present forms, with those on the modern Gnathophausia 

 and Tealliocaris and other Palasozoic genera, as well as in the Mezozoic Tropifer,^ 

 appears to be more than a coincidence arising from similarity of environment, and more 

 probably points to community of descent. It is unfortunate that the state of pre- 

 servation does not allow of any definite knowledge of the nature and position of the 

 special breathing organs that must have been a necessity to such large and muscular 

 organisms. Such fragmentary evidence as is forthcoming is in favour of their having 

 been developed from the free trunk segments, and that they were probably podobran- 

 chiate. Nothing resembling the gill tufts of the Squillids has been found near tlie 

 bases of the pleopods. The view taken by the present writer is that, while they are 

 well within the Schizopod sub-order, they may be looked on as having taken on 

 Squillid characters, and may even have been the early progenitors of the Squillid stock. 



Family ANASPII).a<:. 



Remarks. — This family was erected by G. M. Thomson, of Dunediii, New Zealand, 

 in 1894 to include rhe recent Anaspides tasmanioi Thomson, still living in tlie 



' CJould, Quart. Journ. Geol. Soc, 1857, vol. xiii., p. 360, figs. 1-.3. 



