550 H. WOODWARD ON FOSSIL CRUSTACEA. 
With the exception of the small anterior thoracic one (xtv), 
each abdominal segment (xv—xvm1), has a single oblong punctum on 
either side near the lateral margin of the tergum; and each of the 
three most posterior somites (xvi—xvui1), bears two small subcentral 
puncta on its anterior border, whilst the two hindmost rings (xv 
& xvut) have each a single central punctum on its posterior border. 
The epimeral portion of each somite is separated from its tergal 
portion by a well-defined and prominent ridge running parallel to 
the lateral border, which is truncated and marked by a second ridge 
on its margin, the latero-posterior angle of each segment being 
produced backwards into a small acute tooth. As is characteristic 
of the modern Squille, the abdominal segments of this fossil form 
increase in breadth from the thorax backwards, the xvth measuring 
27 millims. over the tergum, and the xvimth measuring 34 millims, 
The length of the segments is as follows ;— 
xivth (thoracic) 4 millims. long. 
xvth (abdominal) 6 __,, 
xvith 29 8 ey) 9 
xvith ze OF 
XeVEE ae 8 
rr) 
39 39 
The estimated length of the three remaining segments may be 
arrived at pretty correctly by measuring from the hinder border 
of the xvrmth somite to the margin of the telson, or xxist somite, 
which is indicated upon the nodule by a line of projecting spines 
marking its posterior border. 
Estimated length of xrxth (abdominal) segment 8 millims. 
99 23 xxth 99 99 10 9? 
x a xxist % on telsonul7 ia; 
A comparison of our fossil with various recent species has been 
made. It differs from Pseudosquilla Lessoni in that the segments in 
the latter are quite smooth and there are no lateral ridges or puncta. 
In Gonodactylus chiragra and in Gt. cultrifer the body-segments 
are also smooth, without ridges. 
In Squilla mantis there are two dorsal ridges and two epimeral 
ridges on each somite. 
In the British Squilla Desmarestii (Pl. XXVI. fig. 2) there are no 
dorsal ridges, but there are two epimeral ridges on each somite. 
In a recent Squilla brought home by J. Beete Jukes (when natu- 
ralist on board H.M.S. ‘Fly’ in 1842-3-4) from Australia, nearly 
allied to S. Desmarestii, but not namedt, the dorsal ridges are also 
absent ; and there are only two lateral ridges on the epimera. In 
this species then, so widely distributed, we find the nearest living 
ally to our London-Clay fossil. 
I would propose for this new Eocene form the name of Squilla 
* The margin of this segment is slightly imperfect ; it may therefore perhaps 
have been deeper. 
+ I am indebted to my colleague Dr. A. Giinther, I.R.S., Keeper of the Zoo- 
logical Department, for kindly giving me facility for examining and comparing 
this fossil with the fine series of recent specimens in the Museum. 
