1917 Fasten: on Decapoda 295 



discussing this topic, says: "The behavior of the American lobster at 

 the time of pairing and extrusion of the eggs has probably never been 

 witnessed in a state of nature, and certainly but seldom in any of the 

 higher Crustacea." On our Pacific coast more investigation on the breeding 

 habits of the shrimp and the edible crab would be very desirable, partic- 

 ularly from an economic standpoint. 



Secondly, the longevity of the spermatozoa is another topic of vital 

 importance in conjunction with the Decapoda. Most investigators working 

 on the Decapoda agree that the spermatozoa can remain dormant for long 

 periods of time, but no accurate information is available concerning the 

 length of time or the conditions necessary to preserve the life of these male 

 germ cells. 



Thirdly, more knowledge is needed concerning fertilization in the 

 Decapoda. The investigations on this toj^ic have been so few and opin- 

 ions have differed so widely that there is room for more extensive research 

 along this line. 



This entire discussion might well be concluded with the following 

 significant remarks from Herrick (1909). In speaking of the pairing of 

 higher crutacea Herricks says: "There are three subjects, apart from 

 the more special problems of cytology, concerning which exact knowledge 

 is particularly needed. These are: (1) The exact role played by the 

 cement-producing organ: (2) the kind of stimulus or stimuli needed to 

 arouse the sleeping sperm in its receptable, set it in motion, and direct its 

 course to the eggs; and (3) more light on the action of the rays, and the 

 "explosive capsule," by means of which recent students have endeavored 

 to explain the forced entrance of the head of the sperm into the egg. Di- 

 rect observations are too limited at present to afford a basis for the final 

 settlement of any of these matters." 



7. BIBLIOGRAPHY 



Allen, B. jNL, 1916. Notes on the Spiny Lobster (Panuliriis interruptus) 



of the California Coast. Univ. Calif. Pub. Zool. 16:139-152. 

 Binford, R., 1913. The Germ Cells and the Process of Fertilization in the 



Crab, Menippe mercenaria. Jour. Morph. 24:147-202. 

 Caiman, W. T., 1909. Crutacea. A Treatise on Zoology, edited by Sir 



Ray Lankester. Part VII, fascicle 3. A. & C. Black, London. 

 Dahlgren, U., & Kepner, Wm. A., 1908. Principles of Animal Histology. 



Macmillan & Co., New York. 

 Fasten, N., 1915. The Male Reproductive Organs of Some Common Crabs 



of Puget Sound. Puget Sound Marine Sta. Pub. 1:35-41. 

 Fasten, N., 1917. Cilia in the Arthropoda. Science, N. S. (in press). 



