268 DREDGING REPORT, 1862. 
cured by Mr. G. 8. Brady, from a fishing boat at Sunderland. 
I have thus arrived at afar more accurate knowledge of its 
character, than could be obtained from the original type, and 
find that an extraordinary range of variation in the form and 
toothing of the rostrum must be allowed to the species. 
The colouring of H. securifrons is most gorgeous—brilliant 
crimson spotted with canary yellow. ‘ 
The carapace, which is very deep and gibbous, has its front 
margin armed with four pairs of spines;* two of these are placed 
together above the eyes, and near the base of the rostrum; a 
third is situated immediately below the eyes and the fourth at 
the angle formed by the junction of the anterior and lateral 
margins. 
The rostrum in the mature animal assumes the form of a deep, 
flattened, hatchet-shaped plate, ending ina strong tooth; the 
carapace is also keeled and toothed above, through two-thirds of 
its length. The variation in the armature of the rostrum will be 
best understood by the description of several examples selected 
on account of their difference in size. 
Number 1 was the largest specimen obtained, which measured 
two inches and a quarter long, while the total length of the 
smallest specimen, number 9, scarcely exceeded three-quarters of 
an inch. 
1. 13; 4; 4 and 5—that is 13 teeth on the upper side of the 
rostrum, and five on the lower; 4 of the 15 upper teeth 
situated on the carapace; the widest space between any 
two teeth is between the 4th and 5th. (Pl. XIL, figs. 1,2.) 
i.) Ac A and 7.  (Cble axe tio7 3.) 
sol 42and 5. g(elepxelili atic 7) 
; 4; 4and 5. (Pl. XII, fis. 5.) 
; 4; 4 and 5. 
4; 4 and 5; young. 
A; 
ao wa 
5 wie a 
3 
5 and 6; young. 
GOES Cie CAE Ine pole 
i 
= 
exjao I 
; 38; 3 and 4; young. 
9. 2; 3and 4; young. (Pl. XIL., fig. 6.) 
(Ulery 
* In the Brit. Assoc. Report it was erroneously stated that there were three pair only. 
Two spines, however, instead of one, are usually present above the eye; though in one 
instance I could not detect the second spine in that position. 
