48 DUBLIN NATUEAL HISTOEY SOCIETY. 



of this species. I have figured (Plate X.) the best-marked varieties, 

 which occurred in the following proportions : — 



Plate X, Fig. 1. — «, Normal type; rostrum nearly straight; apex 

 bidentate, directed upwards, upper tooth shortest; below two teeth, 

 the anterior much posterior to the upper tooth of apex ; proportional 

 frequency of occurrence, 63 per cent. 



Fig. 2. — J, Rostrum straight ; apex tridentate, teeth directed for- 

 wards, upper and lower teeth nearly equal in length ; below, one tooth 

 only ; proportional frequency, 25 per cent 



Fig. 3. — Cy Rostrum strongly curved upwards, scimitar-shaped; 

 apex tridentate, upper tooth slightly longer than lower ; below, a single 

 tooth ; proportion, 8 per cent. N. B. The whole animal is much slen- 

 derer than the normal type : query, a species ? 



Fig. 4. — d, Rostrum straight ; apex broadly truncated, directed for- 

 wards, quadridentate, apical teeth very minute ; below, two teeth ; pro- 

 portion, 2 per cent. 



Fig. 6. — e, Rostrum straight; apex acuminate, simple, directed 

 upwards ; rostrum with two teeth below. One specimen out of 300 

 examined. 



Fig. 5.—/, Rostrum straight; apex bifid; rostrum with three teeth 

 below, viz., one beneath apex and two closely approximated in the 

 broadest portion of the rostrum. One specimen. 



All these specimens, in addition, have the basal superior tooth (cha- 

 racteristic of the species). Another curious form had the the rostrum 

 very much curved upwards, apex simple, and teeth below absent. These 

 all were from the same pools, in company with the next species, My sis 

 chameleon, Carcinus mcenas, Cancer pagurus, and that strange edrioph- 

 thalmous Crustacea, Apseudes talpa^ its first record, I believe, on the 

 Irish coasts. 



For distribution, see Paper read in April. 



H. Cranchii (Plate X., Figs. 7 and 8). — In the same pools with last, 

 but rarer ; in spawn in May ; spawn of a chocolate-brown colour ; va- 

 rieties with three and four teeth on the rostrum occur. 



II. pusiola {Kroyer) (Plate IX., Fig. 2, a, h, c; and Plate X., 

 Figs. 9, 10). — I first met this species, in 1854, in Dalkey Sound, when 

 I laid it aside as a variety of iT. Cranchii. The constancy of its charac- 

 ters have since caused me to alter this opinion, and, not finding it de- 

 scribed in any of the English or French authorities, I was led to de- 

 scribe it as new, under the name of H. Andrewsii. Since then, however, 

 a paper of Kroyer' s on the Hippolytes of the North, published in the 

 *' Royal Danish Society's Transactions," has come into my hands, in 

 which I find a species described as H. pusiola, which I must look on 

 as identical with that under consideration : I, therefore, feel compelled 

 to adopt Kroyer' s name, for the present, or until better informed on the 

 subject. 



The species is known to the English naturalists, by whom it is looked 

 on as — ^that zoological conveniency — a "• mere variety" oill. Cranchii; 



