Unlike lymphadenitis, a condition associated with some definite infectious or toxic cause, systemic hyperplasia of the lymphatic tissue may be apparently primary and causeless. In a pathological and clinical sense alike these hyperplasias are protean in their manifestation, making a satisfactory classification extremely difficult. For our purposes they are divisible into acute and chronic, associated with an increased number of circulating lymphocytes and without such a lymphocytosis. The first, acute systemic lymphatic hyperplasia, is known in man as status thymicolymphaticus, a well recognized condition chiefly encountered in youthful males having some of the stigmata of the opposite sex. There is no record, nor have I any recollection of a pathological state in a wild animal comparable to this condition. If acute generalized lymph node increase be associated with lymphocytosis, acute lymphatic leucemia exists; there is no case in our records. Chronic enlargement of lymph nodes with increase of circulating mononuclears is chronic lymphatic leucemia; a case of this has been cited under leucemia. LYMPHOMATOSIS. Chronic enlargements of the lymphatic tissues without leucemic blood present a bewildering number of varieties, the best known names of which are Hodgkin’s disease, aleucemic leucemia, pseudoleucemia and lymphomatosis. On occasion they are at first localized tumors, being generalized only late in the course; under these circumstances they are usually classed with neoplasms in the form of leucosarcoma and lymphosarcoma. Examples of lymphatic disease answering the above description are limited to two, but even these must be explained in certain particulars. There has already been quoted under leucemia a case of a common Marmoset (_Callithrix jacchus_) which was probably aleucemic leucemia of the myeloid variety; the enlargement of lymphatic nodes was trifling. The case to be cited answers in most respects to the descriptions of systemic lymphomatosis, but there were found two conditions, enteritis and parasitism, which might be responsible for sufficient general toxemia to stimulate lymph nodes and follicles to a state of active growth. Even accepting these two cases as examples of this group, it is very plain that chronic systemic primary lymphatic hyperplasia is an exceedingly rare entity in wild animals. There has been no case resembling Hodgkin’s disease of man. California Hair Seal (_Zalophus californianus_). Young ♂ four months old. Appeared to be in good health, no loss of flesh or activity. DIAGNOSIS.—Lymphomatosis. Fatty degeneration of kidneys. Emphysema. Chronic follicular and catarrhal enteritis. Nematodes in intestines.