228 CARCINOLOGICAL STUDIES. 



perhaps not quite exact and may be a little too high. 

 The distance between the internal orbital angles is just 

 half as long as the length of the cephalothorax , quite as 

 in Heterop. serratifrons , and as regards the other propor- 

 tions , both species likewise agree with one another. 



5. Heteropanope tridentata Maitland. 

 (Fig. 1). 



Pilumnus tridentatus, Maitland, Naamlijst van Nederlandsche 

 Sdiaaldieren , in: Tijdschrift der Nederlandsche Dierkundige Veree- 

 niging, Deel I, 1873, p. 232. — Hoek, lets over Pilumnus triden- 

 tatus Maitland , in : Tijdschrift der Nederlandsche Dierkundige Ver- 

 eeniging, Deel II, 1876, p. 243: pi. XIV, fig. 12-16. 



Heteropanope tridentata, de Man, in: Zoolog. .Jahrbücher von 

 J. W. Spengel, Bd. IV, 1889, S. 422. 



This interesting species, hitherto only known from 

 Holland , was first distinguished and shortly described by 

 Maitland. It is found in the Zuiderzee, not only on its 

 shores, but also near the island of Urk, further in the IJ 

 near Amsterdam and in the Hollandsch Diep. It occurs 

 however not only in seawater, but also in brackish and 

 even in fresh water. Maitland indeed observed these crabs 

 in a freshwater ditch near Haarlem and Hoek found them 

 in the river Amstel and even near the village of Uithoorn 

 at a distance of five hours from Amsterdam and from the 

 seashore. Some time ago Mr. Maitland was so kind as to 

 procure me some specimens of this species, twelve males 

 of somewhat different size and a young female without 

 eggs : according to him the female individuals would be 

 much less frequent than the males , but Dr. Hoek observed 

 quite the contrary and I received from him an ova-bear- 

 ing female, found near urk in August 1890, at a depth 

 of 14 feet. 



This species now ought to be referred to the genus 

 Heteropanope, as it was characterized by me in my »Re- 

 port on the Crustacea of the Mergui Archipelago" (Jour- 

 Notes from the Leyden IMuseuizi, Vol. XIV. 



