294 Puget Sound Marine Sta. Pub. Vol. 1, No. 26 



(3) In the Decapoda studied the inner layer of epithelium consists 

 either of columnar or cuboidal cells. It is glandular in nature and man- 

 ufactures the heavy fluid secretions as well as the spermatophore cases 

 (Figs. 9-14, 18, 20-22, 24 and 25, / and g). Furthermore, in four spe- 

 cies of Decapoda, namely Pagurus setosiis, Astacus leniuscnlus, Homarus 

 americanus and Panulirus interruptus, the cells of this inner epithelium 

 possess cilia (See Figs. 26-34, h). 



That cilia are universally absent in the Arthropoda is an assertion 

 which is commonly met with in many of our leading zoological treatises. 

 In another paper (Fasten, 1917) the author has given a few quotations 

 concerning this question from some of the leading text-books on zoology, 

 and these might well be repeated here. Adam Sedgwick (1909), in his 

 Student's Text-Book on Zoology, Vol. Ill, pages 316-317, in discussing the 

 female reproductive organs of Peripatus, says : "These ducts in the female 

 retain a ciliated lining (Gaffron), the only known instance of the oc- 

 currence of a ciliated tract among the Arthropoda." Parker and Haswell 

 (1910), in their Text-Book of Zoology, Vol. I (Revised Edition), page 526, 

 state: "Arthropods are also characterized by the almost universal absence 

 of cilia." Kingsley (1912), on page 357 of his revised edition of Hert- 

 wig's Manual of Zoology, makes the following assertion concerning cilia 

 in the Arthropoda: "The entire absence of cilia is noteworthy. Ciliated 

 cells have never been found in arthropods." A similar remark is found 

 in the fifth, revised edition of J. Arthur Thomson's (1913) Outlines of 

 Zoology. Thomson, in speaking of the characteristics of the Arthropoda, 

 on page 281 says: "Ciliated epithelium is almost always absent." 



That the above statements are mere assumptions becomes apparent 

 when the data presented in this paper are examined. As already men- 

 tioned, the writer has found splendid examples of ciliated epithelium in 

 four species of Decapoda (Figs. 26-34, h). Furthermore, Gaffron (1885) 

 has found ciliated epithelium in ducts of the female reproductive organs of 

 neotropical species of Peripatus. Also, Vignon (1901) observed a single 

 case of ciliated epithelium in the digestive apparatus of a Chyronomus 

 larva. In the light of these observations it would not be amiss to predict 

 that further investigation in the Arthropoda will in all probability show 

 that cilia are more generally present among the members of this phylum 

 than has hitherto been assumed. 



6. CONCLUDING REMARKS 



In connection with the foregoing studies on the Decapoda, numerous 

 questions have arisen upon which data is lacking. P'irst of all, accurate 

 information is needed concerning the spawning habits of the Decapoda, 

 especially such forms like the lobster, shrimp and crab. Herrick (1909), 



